Fix --target-version flag for unit tests. (psf#4722)

ranjodhsingh1729 · web-flow · commit b3ae57b22a51 · 2025-08-10T18:38:22.000-05:00
diff --git a/tests/data/cases/target_version_flag.py b/tests/data/cases/target_version_flag.py
@@ -0,0 +1,10 @@
+# flags: --minimum-version=3.12 --target-version=py312
+# this is invalid in versions below py312
+class ClassA[T: str]:
+    def method1(self) -> T:
+        ...
+
+# output
+# this is invalid in versions below py312
+class ClassA[T: str]:
+    def method1(self) -> T: ...
diff --git a/tests/util.py b/tests/util.py
@@ -236,8 +236,8 @@ def get_flags_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser()
     parser.add_argument(
         "--target-version",
-        action="append",
-        type=lambda val: TargetVersion[val.upper()],
+        action="store",
+        type=lambda val: (TargetVersion[val.upper()],),
         default=(),
     )
     parser.add_argument("--line-length", default=DEFAULT_LINE_LENGTH, type=int)
@@ -258,7 +258,7 @@ def get_flags_parser() -> argparse.ArgumentParser:
         default=None,
         help=(
             "Minimum version of Python where this test case is parseable. If this is"
-            " set, the test case will be run twice: once with the specified"
+            " set, the test case will be run twice: once without the specified"
             " --target-version, and once with --target-version set to exactly the"
             " specified version. This ensures that Black's autodetection of the target"
             " version works correctly."
